What medical marijuana can and can’t do for your health

Medical marijuana plants are pictured as they dry in the Los Angeles area.

Mario Anzuoni/Reuters

Medical marijuana may not cure all that ills you

Cannabis may ease your chronic pain, but pass on the spliff if you’re worried about anxiety. Those are two takeaways from a federal advisory released Thursday by the National Academies of Sciences, Engineering, and Medicine. The comprehensive review pinpoints the conditions where cannabis can provide a benefit and where it can’t.

Laws are certainly changing. Last year’s ballot measures saw more states vote on marijuana access than ever before. To date, 28 states, the District of Columbia, Guam and Puerto Rico have legalized medical marijuana, while eight of those states and the District also allow recreational cannabis.“We conducted an in-depth and broad review of the most recent research to establish firmly what the science says and to highlight areas that still need further examination,” Marie McCormick, a Harvard pediatrician who chaired the review panel, said in a statement. “As laws and policies continue to change, research must also.”

Yet despite 20 years of legal marijuana usage, the clinical benefits of the substance remain poorly understood for many diseases and conditions. Federal law still classifies marijuana as illegal, which has stifled when and where it can be used for scientific studies.

So, McCormick and 15 other medical experts spent most of last year combing through more than 10,000 studies on cannabis to comprehend where this medical field stands and what researchers should explore next. Their review looked at studies involved in everything from anorexia to Parkinson’s disease to cancer to car crashes. They rated the strength of the evidence for each condition as for “conclusive or substantial,” “moderate,” or “limited.” Overall, the panel made 100 conclusions on the health impacts of cannabis use.

Along with the conclusive evidence that cannabis can help chronic pain, the team found strong support that marijuana soothes multiple sclerosis symptoms and nausea during chemotherapy. However, they found insufficient support that marijuana can cure cancer and aid conditions like traumatic brain injury.